Density phase separation device

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application No. 61/082,356, filed Jul. 21, 2008, entitled “Density Phase Separation Device”, and to U.S. Provisional Patent Application No. 61/082,365 filed Jul. 21, 2008, entitled “Density Phase Separation Device”, the entire disclosures of each of which are herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention relates to a device for separating heavier and lighter fractions of a fluid sample. More particularly, this invention relates to a device for collecting and transporting fluid samples whereby the device and fluid sample are subjected to centrifugation in order to cause separation of the heavier fraction from the lighter fraction of the fluid sample.

2. Description of Related Art

Diagnostic tests may require separation of a patient's whole blood sample into components, such as serum or plasma, (the lighter phase component), and red blood cells, (the heavier phase component). Samples of whole blood are typically collected by venipuncture through a cannula or needle attached to a syringe or an evacuated blood collection tube. After collection, separation of the blood into serum or plasma and red blood cells is accomplished by rotation of the syringe or tube in a centrifuge. In order to maintain the separation, a barrier must be positioned between the heavier and lighter phase components. This allows the separated components to be subsequently examined.

A variety of separation barriers have been used in collection devices to divide the area between the heavier and lighter phases of a fluid sample. The most widely used devices include thixotropic gel materials, such as polyester gels. However, current polyester gel serum separation tubes require special manufacturing equipment to both prepare the gel and fill the tubes. Moreover, the shelf-life of the product is limited. Over time, globules may be released from the gel mass and enter one or both of the separated phase components. These globules may clog the measuring instruments, such as the instrument probes used during the clinical examination of the sample collected in the tube. Furthermore, commercially available gel barriers may react chemically with the analytes. Accordingly, if certain drugs are present in the blood sample when it is taken, an adverse chemical reaction with the gel interface can occur.

Certain mechanical separators have also been proposed in which a mechanical barrier can be employed between the heavier and lighter phases of the fluid sample. Conventional mechanical barriers are positioned between heavier and lighter phase components utilizing differential buoyancy and elevated gravitational forces applied during centrifugation. For proper orientation with respect to plasma and serum specimens, conventional mechanical separators typically require that the mechanical separator be affixed to the underside of the tube closure in such a manner that blood fill occurs through or around the device when engaged with a blood collection set. This attachment is required to prevent the premature movement of the separator during shipment, handling, and blood draw. Conventional mechanical separators are affixed to the tube closure by a mechanical interlock between the bellows component and the closure. One example of such a device is described in U.S. Pat. No. 6,803,022.

Conventional mechanical separators have some significant drawbacks. As shown in <figref idrefs="DRAWINGS">FIG. 1</figref>, conventional separators include a bellows <b>34</b> for providing a seal with the tube or syringe wall <b>38</b>. Typically, at least a portion of the bellows <b>34</b> is housed within, or in contact with a closure <b>32</b>. As shown in <figref idrefs="DRAWINGS">FIG. 1</figref>, as the needle <b>30</b> enters through the closure <b>32</b>, the bellows <b>34</b> is depressed. This creates a void <b>36</b> in which blood may pool during insertion or removal of the needle. This can result in sample pooling under the closure, device pre-launch in which the mechanical separator prematurely releases during blood collection, trapping of a significant quantity of fluid phases, such as serum and plasma, and/or poor sample quality. Furthermore, previous mechanical separators are costly and complicated to manufacture due to the complicated multi-part fabrication techniques.

Accordingly, a need exists for a separator device that is compatible with standard sampling equipment and reduces or eliminates the aforementioned problems of conventional separators. A need also exists for a separator device that is easily used to separate a blood sample, minimizes cross-contamination of the heavier and lighter phases of the sample during centrifugation, is independent of temperature during storage and shipping and is stable to radiation sterilization.

SUMMARY OF THE INVENTION

The present invention is directed to an assembly for separating a fluid sample into a higher specific gravity phase and a lower specific gravity phase. Desirably, the mechanical separator of the present invention may be used with a tube, and the mechanical separator is structured to move within the tube under the action of applied centrifugal force in order to separate the portions of a fluid sample. Most preferably, the tube is a specimen collection tube including an open end, a second end, and a sidewall extending between the open end and second end. The sidewall includes an outer surface and an inner surface and the tube further includes a closure disposed to fit in the open end of the tube with a resealable septum. Alternatively, both ends of the tube may be open, and both ends of the tube may be sealed by elastomeric closures. At least one of the closures of the tube may include a needle pierceable resealable septum.

The mechanical separator may be disposed within the tube at a location between the top closure and the bottom of the tube. The separator includes opposed top and bottom ends and includes a float having a pierceable head, a ballast, and a bellows. The components of the separator are dimensioned and configured to achieve an overall density for the separator that lies between the densities of the phases of a fluid sample, such as a blood sample.

In one embodiment, the mechanical separator for separating a fluid sample into first and second phases within a tube includes a float having a passageway extending between first and second ends thereof with a pierceable head enclosing the first end of the float. The mechanical separator also includes a ballast longitudinally moveable with respect to the float, and a bellows extending between a portion of the float and a portion of the ballast, the bellows adapted for deformation upon longitudinal movement of the float and the ballast. The bellows of the mechanical separator are isolated from the pierceable head. In one embodiment, the float has a first density and the ballast has a second density, wherein the first density is less than the second density.

The pierceable head of the mechanical separator is structured to resist deformation upon application of a puncture tip therethrough. The pierceable head may comprise a rim portion for engagement with a closure, and optionally, the rim portion may define at least one notch.

The pierceable head may be received at least partially within an upper recess of the float. The bellows may be circumferentially disposed about at least a portion of the float. In one configuration, the pierceable head and the bellows are isolated by a portion of the float. In another configuration, the pierceable head and the bellows are isolated by a neck portion of the float. In yet another configuration, the bellows includes an interior wall defining a restraining surface, and the float includes a shoulder for engaging the restraining surface.

The ballast can define an interlock recess for accommodating a portion of the bellows for attachment thereto. In this manner, the bellows and the ballast can be secured. Additionally, the ballast can include an exterior surface defining an annular shoulder circumferentially disposed within the exterior surface to assist in the assembly process.

In one embodiment of the mechanical separator, the float can be made of polypropylene, the pierceable head can be made of a thermoplastic elastomer (TPE), such as Kraton®, commercially available from Kraton Polymers, LLC, the bellows can also be made of a thermoplastic elastomer, and the ballast can be made of polyethylene terephthalate (PET).

In another embodiment, a separation assembly for enabling separation of a fluid sample into first and second phases includes a tube, having an open end, a second end, and a sidewall extending therebetween, and a closure adapted for sealing engagement with the open end of the tube. The closure defines a recess and the separation assembly includes a mechanical separator releasably engaged within the recess. The mechanical separator includes a float having a passageway extending between first and second ends thereof with a pierceable head enclosing the first end of the float. The mechanical separator also includes a ballast longitudinally moveable with respect to the float, and a bellows extending between a portion of the float and a portion of the ballast, the bellows adapted for deformation upon longitudinal movement of the float and the ballast. The bellows of the mechanical separator are isolated from the pierceable head. In one embodiment, the float has a first density and the ballast has a second density, wherein the first density is less than the second density.

The pierceable head of the float may be structured to resist deformation upon application of a puncture tip therethrough. In one configuration, the pierceable head and the bellows are isolated by a portion of the float. In another configuration, the pierceable head and the bellows are isolated by a neck portion of the float. Optionally, the bellows includes an interior wall defining a restraining surface, and the float comprises a shoulder for engaging the restraining surface. The ballast may define an interlock recess for accommodating a portion of the bellows for attachment thereto.

In another embodiment, the mechanical separator includes a first sub-assembly including a float having a pierceable head enclosing a first end thereof, and a second sub-assembly having a ballast and a bellows. The first sub-assembly may have a first density and the second sub-assembly may have a second density, the second density being greater than the first density of the first sub-assembly. The first sub-assembly and the second sub-assembly may be attached through the bellows such that the ballast is longitudinally movable with respect to the float upon deformation of the bellows. The bellows of the second sub-assembly is isolated from the pierceable head of the first sub-assembly.

In yet another embodiment of the present invention, a method of assembling a mechanical separator includes the steps of providing a first sub-assembly, the first sub-assembly including a float with a neck and a pierceable head, providing a second sub-assembly, the second sub-assembly including a bellows extending from a ballast and including an interior restraining surface, and joining the first sub-assembly with the second sub-assembly. The first sub-assembly and the second sub-assembly are joined such that the neck of the float is in mechanical interface with the interior restraining surface of the bellows. The float may have a first density and the ballast may have a second density greater than the first density of the float. Optionally, the joining step includes inserting and guiding the float through an interior of the bellows until the neck of the float is in mechanical interface with the interior restraining surface of the bellows. The ballast may also include an exterior surface defining an annular shoulder circumferentially disposed thereabout for receipt of a mechanical assembler therein.

In another embodiment of the present invention, a separation assembly for enabling separation of a fluid sample into first and second phases includes a closure adapted for sealing engagement with a tube, with the closure defining a recess. The separation assembly further includes a mechanical separator. The mechanical separator includes a float defining a passageway extending between first and second ends thereof with a pierceable head enclosing the first end of the float. The pierceable head is releasably engaged within the recess. The mechanical separator also includes a ballast longitudinally movable with respect to the float, the ballast having a second density greater than the first density of the float. The mechanical separator further includes a bellows extending between a portion of the float and a portion of the ballast, the bellows being adapted for deformation upon longitudinal movement of the float and the ballast with the bellows being isolated from the pierceable head.

In one configuration, the interface between the closure and the mechanical separator occurs only between the pierceable head and the recess. The separation assembly may also be configured such that the mechanical separator may be released from the closure without elongation of the deformable bellows.

In accordance with another embodiment of the present invention, a mechanical separator for separating a fluid sample into first and second phases within a tube includes a float comprising a passageway extending between a first upwardly oriented end and a second downwardly oriented end thereof. The mechanical separator also includes a ballast longitudinally movable with respect to the float, and a bellows extending between a portion of the float and a portion of the ballast, the bellows being adapted for deformation upon longitudinal movement of the float and the ballast, and isolated from the first upwardly oriented end of the float.

In accordance with another embodiment of the present invention, a separation assembly for enabling separation of a fluid sample into first and second phases includes a tube having an open end, a second end, and a sidewall extending therebetween. The separation assembly also includes a closure adapted for sealing engagement with the open end of the tube, the closure defining a recess, and a mechanical separator releasably engaged within the recess. The mechanical separator includes a float having a passageway extending between a first upwardly oriented end and a second downwardly oriented end thereof. The mechanical separator also includes a ballast longitudinally movable with respect to the float, and a bellows extending between a portion of the float and a portion of the ballast. The bellows being adapted for deformation upon longitudinal movement of the float and the ballast, and isolated from the first upwardly oriented end of the float. Optionally, the separation assembly is adapted to introduce a fluid sample into the tube and around the mechanical separator without passing through the mechanical separator.

In accordance with yet another embodiment of the present invention, a mechanical separator for separating a fluid sample into first and second phases within a tube includes a float defining an interior having a moveable plug disposed therein. The moveable plug is adapted to transition from a first position to a second position along a longitudinal axis of the float in response to expansion of the fluid sample within the interior of the float.

In one configuration, the float defines a transverse hole and the moveable plug defines a transverse hole substantially aligned with the transverse hole of the float in the first position and blocked by a portion of the float in the second position. Optionally, the moveable plug is restrained within the interior of the float by a pierceable head. The mechanical separator may also include a ballast longitudinally movable with respect to the float, and a bellows extending between a portion of the float and a portion of the ballast. The bellows may be adapted for deformation upon longitudinal movement of the float and the ballast, and may be isolated from the first upwardly oriented end of the float.

In accordance with yet a further embodiment of the present invention, a mechanical separator for separating a fluid sample into first and second phases within a tube includes a float, a ballast longitudinally movable with respect to the float, and a bellows extending between a portion of the float and a portion of the ballast. The bellows may be adapted for deformation upon longitudinal movement of the float and the ballast, and may be adapted to separate at least partially from the float to allow venting of gas therebetween.

The assembly of the present invention is advantageous over existing separation products that utilize separation gel. In particular, the assembly of the present invention will not interfere with analytes, whereas many gels interact with bodily fluids. Another attribute of the present invention is that the assembly of the present invention will not interfere with therapeutic drug monitoring analytes.

The assembly of the present invention is also advantageous over existing mechanical separators in that the separate pierceable head and bellows allows for isolating the seal function of the bellows from the needle interface of the mechanical separator. This enables different materials or material thicknesses to be used in order to optimize the respective seal function and needle interface function. Also, this minimizes device pre-launch by providing a more stable target area at the puncture tip interface to reduce sample pooling under the closure. In addition, pre-launch is further minimized by precompression of the pierceable head against the interior of the stopper. The reduced clearance between the exterior of the float and the interior of the ballast minimizes the loss of trapped fluid phases, such as serum and plasma. Additionally, the assembly of the present invention does not require complicated extrusion techniques during fabrication, and may optimally employ two-shot molding techniques.

As described herein, the mechanical separator of the present invention does not occlude an analysis probe like traditional gel tubes. Further details and advantages of the invention will become clear from the following detailed description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idrefs="DRAWINGS">FIG. 1</figref> is a partial cross-sectional side view of a conventional mechanical separator.

<figref idrefs="DRAWINGS">FIG. 2</figref> is an exploded perspective view of a mechanical separator assembly including a closure, a bellows, a ballast, a pierceable head, a float, and a collection tube in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 3</figref> is a perspective view of the bottom surface of the closure of <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 4</figref> is a cross-sectional view of the closure of <figref idrefs="DRAWINGS">FIG. 2</figref>, taken along line <b>4</b>-<b>4</b> of <figref idrefs="DRAWINGS">FIG. 3</figref>.

<figref idrefs="DRAWINGS">FIG. 5</figref> is a perspective view of the pierceable head of <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 6</figref> is a top view of the pierceable head of <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 7</figref> is a side view of the pierceable head of <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 8</figref> is a cross-sectional view of the pierceable head of <figref idrefs="DRAWINGS">FIG. 2</figref>, taken along line <b>8</b>-<b>8</b> of <figref idrefs="DRAWINGS">FIG. 7</figref>.

<figref idrefs="DRAWINGS">FIG. 9</figref> is a side view of the float of <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 10</figref> is a cross-sectional view of the float of <figref idrefs="DRAWINGS">FIG. 2</figref>, taken along line <b>10</b>-<b>10</b> of <figref idrefs="DRAWINGS">FIG. 9</figref>.

<figref idrefs="DRAWINGS">FIG. 11</figref> is close-up cross-sectional view of a portion of the float of <figref idrefs="DRAWINGS">FIG. 2</figref> taken along section XI of <figref idrefs="DRAWINGS">FIG. 10</figref>.

<figref idrefs="DRAWINGS">FIG. 12</figref> is a top view of the float of <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 13</figref> is a perspective view of the bellows of <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 14</figref> is a side view of the bellows of <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 15</figref> is a cross-sectional view of the bellows of <figref idrefs="DRAWINGS">FIG. 2</figref>, taken along line <b>15</b>-<b>15</b> of <figref idrefs="DRAWINGS">FIG. 14</figref>.

<figref idrefs="DRAWINGS">FIG. 16</figref> is a perspective view of the ballast of <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 17</figref> is a side view of the ballast of <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 18</figref> is a cross-sectional view of the ballast of <figref idrefs="DRAWINGS">FIG. 2</figref>, taken along line <b>18</b>-<b>18</b> of <figref idrefs="DRAWINGS">FIG. 17</figref>.

<figref idrefs="DRAWINGS">FIG. 19</figref> is a close-up cross-sectional view of a portion of the bellows of <figref idrefs="DRAWINGS">FIG. 2</figref> taken along section IXX of <figref idrefs="DRAWINGS">FIG. 18</figref>.

<figref idrefs="DRAWINGS">FIG. 20</figref> is a perspective view of the mechanical separator including the pierceable head, float, bellows, and ballast in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 21</figref> is a front view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 20</figref>.

<figref idrefs="DRAWINGS">FIG. 22</figref> is a cross-sectional view of a mechanical separator of <figref idrefs="DRAWINGS">FIG. 20</figref>, taken along line <b>22</b>-<b>22</b> of <figref idrefs="DRAWINGS">FIG. 21</figref>.

<figref idrefs="DRAWINGS">FIG. 23</figref> is a cross-sectional view of a mechanical separator affixed to a closure in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 24</figref> is a partial cross-sectional perspective view of a mechanical separator assembly including a tube, a mechanical separator positioned within the tube, a closure, a shield surrounding the closure and a portion of the tube, and a needle accessing the tube in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 25</figref> is a front view of an assembly including a tube having a closure and a mechanical separator disposed therein in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 26</figref> is a cross-sectional front view of the assembly of <figref idrefs="DRAWINGS">FIG. 25</figref> having a needle accessing the interior of the tube and an amount of fluid provided through the needle into the interior of the tube in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 27</figref> is a cross-sectional front view of the assembly of <figref idrefs="DRAWINGS">FIG. 25</figref> having the needle removed therefrom during use and the mechanical separator positioned apart from the closure in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 27A</figref> is a partial cross-sectional front view of an assembly including a tube having a mechanical separator disposed therein under load in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 27B</figref> is a partial cross-sectional front view of the assembly of <figref idrefs="DRAWINGS">FIG. 27A</figref> after centrifugation.

<figref idrefs="DRAWINGS">FIG. 28</figref> is a cross-sectional front view of the assembly of <figref idrefs="DRAWINGS">FIG. 25</figref> having the mechanical separator separating the less dense portion of the fluid from the denser portion of the fluid in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 29</figref> is a perspective view of an alternative embodiment of a mechanical separator having a ballast snap in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 30</figref> is a cross-sectional front view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 29</figref>.

<figref idrefs="DRAWINGS">FIG. 31</figref> is a front view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 29</figref>.

<figref idrefs="DRAWINGS">FIG. 32</figref> is a cross-sectional view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 29</figref> taken along line <b>32</b>-<b>32</b> of <figref idrefs="DRAWINGS">FIG. 31</figref>.

<figref idrefs="DRAWINGS">FIG. 33</figref> is a partial cross-sectional view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 29</figref> taken along section XXXIII of <figref idrefs="DRAWINGS">FIG. 30</figref>.

<figref idrefs="DRAWINGS">FIG. 34</figref> is an alternative embodiment of the partial cross-sectional view of <figref idrefs="DRAWINGS">FIG. 33</figref> having a tapered profile in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 35</figref> is a front view of a first sub-assembly having a pierceable head portion and a float in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 36</figref> is a cross-sectional view of the first sub-assembly of <figref idrefs="DRAWINGS">FIG. 35</figref>.

<figref idrefs="DRAWINGS">FIG. 37</figref> is a perspective view of a second sub-assembly having a bellows and a ballast in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 38</figref> is a partial cross-sectional front view of the second sub-assembly of <figref idrefs="DRAWINGS">FIG. 37</figref>.

<figref idrefs="DRAWINGS">FIG. 39</figref> is a cross-sectional front view of an assembled first sub-assembly and second sub-assembly of a mechanical separator in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 40</figref> is a perspective view of the assembled mechanical separator of <figref idrefs="DRAWINGS">FIG. 39</figref>.

<figref idrefs="DRAWINGS">FIG. 41</figref> is a perspective view of a mechanical separator in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 42</figref> is a front view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 41</figref>.

<figref idrefs="DRAWINGS">FIG. 43</figref> is a left side view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 41</figref>.

<figref idrefs="DRAWINGS">FIG. 44</figref> is a rear view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 41</figref>.

<figref idrefs="DRAWINGS">FIG. 45</figref> is a right side view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 41</figref>.

<figref idrefs="DRAWINGS">FIG. 46</figref> is a top view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 41</figref>.

<figref idrefs="DRAWINGS">FIG. 47</figref> is a bottom view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 41</figref>.

<figref idrefs="DRAWINGS">FIG. 48</figref> is a perspective view of the float of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 41</figref>.

<figref idrefs="DRAWINGS">FIG. 49</figref> is a top perspective view of the pierceable head of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 41</figref>.

<figref idrefs="DRAWINGS">FIG. 50</figref> is a bottom perspective view of the pierceable head of <figref idrefs="DRAWINGS">FIG. 49</figref>.

<figref idrefs="DRAWINGS">FIG. 51</figref> is a cross-sectional front view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 41</figref> positioned within a closure of the present invention.

<figref idrefs="DRAWINGS">FIG. 52</figref> is a front view of a specimen collection container having a closure with the mechanical separator of <figref idrefs="DRAWINGS">FIG. 41</figref> disposed therein.

<figref idrefs="DRAWINGS">FIG. 53</figref> is a cross-sectional front view of the specimen collection container, closure and mechanical separator of <figref idrefs="DRAWINGS">FIG. 52</figref> taken along line <b>53</b>-<b>53</b> of <figref idrefs="DRAWINGS">FIG. 52</figref>.

<figref idrefs="DRAWINGS">FIG. 54</figref> is a partial cross-sectional front view of a closure and a portion of a mechanical separator in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 55</figref> is a perspective of the top view of the closure of <figref idrefs="DRAWINGS">FIG. 54</figref>.

<figref idrefs="DRAWINGS">FIG. 56</figref> is a perspective of the bottom view of the closure of <figref idrefs="DRAWINGS">FIG. 54</figref>.

<figref idrefs="DRAWINGS">FIG. 57</figref> is a cross-sectional front view of an alternative closure and a portion of a mechanical separator in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 58</figref> is a cross-sectional side view of the alternative closure of <figref idrefs="DRAWINGS">FIG. 57</figref> taken along line <b>58</b>-<b>58</b> of <figref idrefs="DRAWINGS">FIG. 57</figref> and a portion of a mechanical separator in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 58A</figref> is a cross-sectional front view of the alternative closure of <figref idrefs="DRAWINGS">FIGS. 57-58</figref> engaged with a specimen collection container having a mechanical separator disposed therein in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 59</figref> is a partial cross-sectional perspective view of a mechanical separator having a moveable plug disposed within the float in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 60</figref> is a cross-sectional front view of the float having a moveable plug disposed therein of <figref idrefs="DRAWINGS">FIG. 59</figref> in an initial position.

<figref idrefs="DRAWINGS">FIG. 61</figref> is a cross-sectional front view of the float and moveable plug of <figref idrefs="DRAWINGS">FIG. 60</figref> in a displaced position.

<figref idrefs="DRAWINGS">FIG. 62</figref> is a partial cross-sectional view of a mechanical separator having a solid float in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 63</figref> is a cross-sectional front view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 62</figref> disposed within a specimen collection container and engaged with a closure.

<figref idrefs="DRAWINGS">FIG. 64</figref> is a cross-sectional front view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 63</figref> having a needle disposed through a portion of the closure for introducing sample into the specimen collection container.

<figref idrefs="DRAWINGS">FIG. 65</figref> is a partial cross-sectional front view of an alternative embodiment of a mechanical separator disposed within a specimen collection container having a separation component in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 66</figref> is a partial cross-sectional front view of an alternative embodiment of a mechanical separator disposed within a specimen collection container having a ribbed protrusion in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 67</figref> is a partial cross-sectional front view of an alternative embodiment of a mechanical separator disposed within a specimen collection container having a cutout in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 68</figref> is a partial cross-sectional front view of the mechanical separator of <figref idrefs="DRAWINGS">FIG. 63</figref> having a washer disposed about a portion of the mechanical separator in accordance with an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 69</figref> is a perspective view of a washer of <figref idrefs="DRAWINGS">FIG. 68</figref>.

<figref idrefs="DRAWINGS">FIG. 70</figref> is a perspective view of an alternative embodiment of the washer of <figref idrefs="DRAWINGS">FIG. 68</figref>.

<figref idrefs="DRAWINGS">FIG. 71</figref> is a cross-sectional front view of a specimen collection container having a closure engaged therewith and having a mechanical separator disposed therein in accordance with an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of the description hereinafter, the words “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal” and like spatial terms, if used, shall relate to the described embodiments as oriented in the drawing figures. However, it is to be understood that many alternative variations and embodiments may be assumed except where expressly specified to the contrary. It is also to be understood that the specific devices and embodiments illustrated in the accompanying drawings and described herein are simply exemplary embodiments of the invention.

As shown in exploded perspective view in <figref idrefs="DRAWINGS">FIG. 2</figref>, the mechanical separator assembly <b>40</b> of the present invention includes a closure <b>42</b> with a mechanical separator <b>44</b>, for use in connection with a tube <b>46</b> for separating a fluid sample into first and second phases within the tube <b>46</b>. The tube <b>46</b> may be a sample collection tube, such as a proteomics, molecular diagnostics, chemistry sample tube, blood or other bodily fluid collection tube, coagulation sample tube, hematology sample tube, and the like. Desirably tube <b>46</b> is an evacuated blood collection tube. In one embodiment, the tube <b>46</b> may contain additional additives as required for particular testing procedures, such as clot inhibiting agents, clotting agents, and the like. Such additives may be in particle or liquid form and may be sprayed onto the cylindrical sidewall <b>52</b> of the tube <b>46</b> or located at the bottom of the tube <b>46</b>. The tube <b>46</b> includes a closed bottom end <b>48</b>, such as an apposing end, an open top end <b>50</b>, and a cylindrical sidewall <b>52</b> extending therebetween. The cylindrical sidewall <b>52</b> includes an inner surface <b>54</b> with an inside diameter “a” extending substantially uniformly from the open top end <b>50</b> to a location substantially adjacent the closed bottom end <b>48</b>.

The tube <b>46</b> may be made of one or more than one of the following representative materials: polypropylene, polyethylene terephthalate (PET), glass, or combinations thereof. The tube <b>46</b> can include a single wall or multiple wall configurations. Additionally, the tube <b>46</b> may be constructed in any practical size for obtaining an appropriate biological sample. For example, the tube <b>46</b> may be of a size similar to conventional large volume tubes, small volume tubes, or microtainer tubes, as is known in the art. In one particular embodiment, the tube <b>46</b> may be a standard 3 ml evacuated blood collection tube, as is also known in the art.

The open top end <b>50</b> is structured to at least partially receive the closure <b>42</b> therein to faun a liquid impermeable seal. The closure includes a top end <b>56</b> and a bottom end <b>58</b> structured to be at least partially received within the tube <b>46</b>. Portions of the closure <b>42</b> adjacent the top end <b>56</b> defines a maximum outer diameter which exceeds the inside diameter “a” of the tube <b>46</b>. As shown in <figref idrefs="DRAWINGS">FIGS. 2-4</figref>, portions of the closure <b>42</b> at the top end <b>56</b> include a central recess <b>60</b> which define a pierceable resealable septum. Portions of the closure <b>42</b> extending downwardly from the bottom end <b>58</b> may taper from a minor diameter which is approximately equal to, or slightly less than, the inside diameter “a” of the tube <b>46</b> to a major diameter that is greater than the inside diameter “a” of the tube <b>46</b> at the top end <b>56</b>. Thus, the bottom end <b>58</b> of the closure <b>42</b> may be urged into a portion of the tube <b>46</b> adjacent the open top end <b>50</b>. The inherent resiliency of closure <b>42</b> can insure a sealing engagement with the inner surface of the cylindrical sidewall <b>52</b> of the tube <b>46</b>.

In one embodiment, the closure <b>42</b> can be formed of a unitarily molded elastomeric material, having any suitable size and dimensions to provide sealing engagement with the tube <b>46</b>. The closure <b>42</b> can also be formed to define a bottom recess <b>62</b> extending into the bottom end <b>58</b>. The bottom recess <b>62</b> may be sized to receive at least a portion of the mechanical separator <b>44</b>. Additionally, a plurality of spaced apart arcuate flanges <b>64</b> may extend around the bottom recess <b>62</b> to at least partially restrain the mechanical separator <b>44</b> therein.

Referring again to <figref idrefs="DRAWINGS">FIG. 2</figref>, the mechanical separator <b>44</b> includes a pierceable head <b>66</b>, a float <b>68</b> engaged with a portion of the pierceable head <b>66</b>, a bellows <b>70</b> disposed about a portion of the float <b>68</b>, and a ballast <b>72</b> disposed about at least a portion of the float <b>68</b> and engaged with the bellows <b>70</b>.

Referring to <figref idrefs="DRAWINGS">FIGS. 5-8</figref>, the pierceable head <b>66</b> of the mechanical separator <b>44</b> may be extruded and/or molded of a resiliently deformable and self-sealable material, such as TPE. The pierceable head <b>66</b> includes an upper rim portion <b>76</b> and a lower portion <b>78</b>, opposite the upper rim portion <b>76</b>. The upper rim portion <b>76</b> may have a generally curved shape for correspondingly mating to the shape of the bottom recess <b>62</b> of the closure <b>42</b>, shown in <figref idrefs="DRAWINGS">FIGS. 3-4</figref>. In order to mitigate pre-launch, the pierceable head <b>66</b> may be precompressed against the bottom recess <b>62</b> of the closure <b>42</b>. In one embodiment, as shown in <figref idrefs="DRAWINGS">FIG. 7</figref>, the upper rim portion <b>76</b> of the pierceable head <b>66</b> has a curvature angle A of about 20 degrees. In another embodiment, the upper rim portion <b>76</b> of the pierceable head <b>66</b> includes a slightly tapered or flattened portion <b>74</b>. The portion <b>74</b> can have any suitable dimensions, however, it is preferable that the portion <b>74</b> have a diameter of from about 0.120 inch to about 0.150 inch.

The portion <b>74</b> of the pierceable head <b>66</b> is structured to allow a puncture tip, shown in <figref idrefs="DRAWINGS">FIG. 26</figref>, such as a needle tip, needle cannula, or probe, to pass therethrough. Upon withdrawal of the puncture tip from the portion <b>74</b>, the pierceable head <b>66</b> is structured to reseal itself to provide a liquid impermeable seal. The flattened shape of the portion <b>74</b> allows for a penetration by the puncture tip without significant deformation. In one embodiment, the portion <b>74</b> of the pierceable head <b>66</b> is structured to resist deformation upon application of a puncture tip therethrough. The generally curved shape of the upper rim portion <b>76</b> and the small diameter of the portion <b>74</b> make the pierceable head <b>66</b> of the present invention more stable and less likely to “tent” than the pierceable region of existing mechanical separators. To further assist in limiting sample pooling and premature release of the separator <b>44</b> from the bottom recess <b>62</b> of the closure <b>42</b>, the portion <b>74</b> of the pierceable head <b>66</b> may optionally include a thickened region, such as from about 0.010 inch to about 0.030 inch thicker than other portions of the upper rim portion <b>76</b> of the pierceable head <b>66</b>.

The pierceable head <b>66</b> also includes a lower portion <b>78</b>, opposite the upper rim portion <b>76</b>, structured to engage at least a portion of the float <b>68</b>, shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. The pierceable head <b>66</b> may define at least one cut-out notch <b>80</b>, shown in <figref idrefs="DRAWINGS">FIGS. 5-6</figref>, extending from the upper rim portion <b>76</b> to the lower portion <b>78</b> and from an outer circumference <b>82</b> of the upper rim portion <b>76</b> to a location <b>84</b> circumferentially inward from the outer circumference <b>82</b>. The cut-out notch <b>80</b> may be provided to allow the upper rim portion <b>76</b> of the pierceable head <b>66</b> to bend, such as upon application of a puncture tip through the access portion <b>74</b>, without significant resulting hoop-stress to the pierceable head <b>66</b>. In one embodiment, a plurality of cut-out notches <b>80</b> may be provided at a plurality of locations about the outer circumference <b>82</b> of the pierceable head <b>66</b>. A plurality of cut-out notches <b>80</b> may enable the pierceable head <b>66</b> to flex in such a manner as to control the release load of the mechanical separator <b>44</b> from the closure <b>42</b>.

As shown in <figref idrefs="DRAWINGS">FIGS. 7-8</figref>, the upper rim portion <b>76</b> of the pierceable head <b>66</b> may include an extended portion <b>82</b> dimensioned to overhang the lower portion <b>78</b>. In one embodiment, the extended portion <b>82</b> of the pierceable head <b>66</b> may be dimensioned to have a diameter “b” that is greater than the diameter “c” of the lower portion <b>78</b>. In another embodiment, the lower portion <b>78</b> of the pierceable head <b>66</b> may be dimensioned for engagement with, such as receipt within, a portion of the float <b>68</b> as shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. In yet another embodiment, as shown in <figref idrefs="DRAWINGS">FIGS. 5-6</figref>, the pierceable head <b>66</b> may be optionally vented with a plurality of slits <b>85</b> created by a post-molding assembly operation. The pierceable head <b>66</b> may include three such spaced slits <b>85</b>.

Referring to <figref idrefs="DRAWINGS">FIGS. 9-12</figref>, the float <b>68</b> of the mechanical separator <b>44</b> is a generally tubular structure <b>90</b> having an upper end <b>86</b>, a lower end <b>92</b>, and a passage <b>94</b> extending longitudinally therebetween. As shown in <figref idrefs="DRAWINGS">FIGS. 9-10</figref>, the float <b>68</b> of the mechanical separator <b>44</b> includes an upper end <b>86</b> defining an upper recess <b>88</b> for receiving the lower portion <b>78</b> of the pierceable head <b>66</b>. The upper end <b>86</b> of the float <b>68</b> has a diameter “d” which may be larger than the diameter “c” of the lower portion <b>78</b> of the pierceable head <b>66</b>, shown in <figref idrefs="DRAWINGS">FIG. 8</figref>, to allow receipt of the pierceable head <b>66</b> therein. In one embodiment, the diameter “d” of the upper end <b>86</b> of the float <b>68</b> is smaller than the diameter “b” of the extended portion <b>82</b> of the pierceable head <b>66</b>, also shown in <figref idrefs="DRAWINGS">FIG. 8</figref>. In another embodiment, the diameter “e” of the tubular structure <b>90</b> of the float <b>68</b> is greater than the diameter “b” of the upper rim portion <b>76</b> of the pierceable head <b>66</b>, therefore, the lower portion <b>78</b> of the pierceable head <b>66</b> may be received within the float <b>68</b> while the extended portion <b>82</b> of the pierceable head <b>66</b> extends beyond the interior of the float <b>68</b> when the pierceable head <b>66</b> and the float <b>68</b> are engaged. Optionally, the diameter “d” of the float <b>68</b> may be equal to the diameter “c” of the pierceable head <b>66</b>. This may be particularly preferable for two-shot molding techniques.

The annular engagement of the lower portion <b>78</b> of the pierceable head <b>66</b> within the recess <b>88</b> establishes a mechanical engagement for providing structural rigidity to the pierceable head <b>66</b>. Such structural rigidity, in combination with the profile and dimensions of the access portion <b>74</b> of the pierceable head <b>66</b>, limits the amount of deformation thereof when a puncture tip is pressed therethrough. In this manner, sample pooling and premature release of the separator <b>44</b> from the closure <b>42</b> can be prevented.

Referring again to <figref idrefs="DRAWINGS">FIGS. 9-12</figref>, the upper end <b>86</b> of the float <b>68</b> also includes a generally tubular neck <b>96</b>. Adjacent the neck <b>96</b>, and extending circumferentially around the longitudinal axis L of the float <b>68</b> is a shoulder <b>98</b> having an exterior surface <b>100</b>. As shown in a close-up view in <figref idrefs="DRAWINGS">FIG. 11</figref> taken along section XI, in one embodiment the exterior surface <b>100</b> has an angled slope B of about 29 degrees to facilitate the shedding of cells around the mechanical separator <b>44</b> during centrifugation.

In another embodiment, a plurality of protrusions <b>102</b> may be located about the shoulder <b>98</b> of the float <b>68</b>. The protrusions <b>102</b> may be a plurality of segmented protrusions spaced about a circumference of float <b>68</b>. The protrusions <b>102</b> may create channels for venting of air from within the mechanical separator <b>44</b> when the mechanical separator <b>44</b> is submerged in fluid during centrifugation. In one embodiment, the venting pathway is created by a hole or series of holes through a wall in the float <b>68</b> adjacent the junction of the bellows <b>70</b> and the float <b>68</b>.

In one embodiment, it is desirable that the float <b>68</b> of the mechanical separator <b>44</b> be made from a material having a density lighter than the liquid intended to be separated into two phases. For example, if it is desired to separate human blood into serum and plasma, then it is desirable that the float <b>68</b> have a density of no more than about 0.902 gm/cc. In another embodiment, the float <b>46</b> can be formed from polypropylene. In yet another embodiment, the pierceable head <b>66</b>, shown in FIGS. <b>2</b> and <b>5</b>-<b>8</b>, and the float <b>68</b>, shown in FIGS. <b>2</b> and <b>9</b>-<b>12</b>, can be co-molded, such as two-shot molded, or co-extruded as a first sub-assembly.

As shown in <figref idrefs="DRAWINGS">FIGS. 13-15</figref> the bellows <b>70</b> are extruded and/or molded of a resiliently deformable material that exhibits good sealing characteristics with the tube material(s). The bellows <b>70</b> is symmetrical about a center longitudinal axis C, and includes an upper end <b>106</b>, a lower end <b>108</b>, and a hollow interior <b>104</b>. The bellows <b>70</b> also defines a deformable sealing portion <b>112</b> positioned between the upper end <b>106</b> and the lower end <b>108</b> for sealing engagement with the cylindrical sidewall <b>52</b> of the tube <b>46</b>, as shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. The bellows <b>70</b> can be made of any sufficiently elastomeric material sufficient to form a liquid impermeable seal with the cylindrical sidewall <b>52</b> of the tube <b>46</b>. In one embodiment, the bellows is TPE and has an approximate dimensional thickness of from about 0.020 inch to about 0.050 inch.

The deformable sealing portion <b>112</b> can have a generally toroidal shape having an outside diameter “f” which, in an unbiased position, slightly exceeds the inside diameter “a” of the tube <b>46</b>, shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. However, oppositely directed forces on the upper end <b>106</b> and the lower end <b>108</b> will lengthen the bellows <b>70</b>, simultaneously reducing the diameter of the deformable sealing section to a dimension less than “a”. Accordingly, the bellows <b>70</b> are adapted to deform upon longitudinal movement of the float <b>68</b> in a first direction and the ballast <b>72</b> in a second opposite direction.

The bellows <b>70</b> can be disposed about, such as circumferentially disposed about, at least a portion of the float <b>68</b>, shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. As shown in <figref idrefs="DRAWINGS">FIGS. 13-15</figref>, the bellows <b>70</b> includes an interior wall <b>114</b> within the interior <b>104</b>. Adjacent the upper end <b>106</b> of the bellows <b>70</b>, the interior wall <b>114</b> defines an interior restraining surface <b>116</b> for mechanical interface with the shoulder <b>98</b> of the float <b>68</b>, shown in <figref idrefs="DRAWINGS">FIGS. 9-12</figref>. In one embodiment, the interior restraining surface <b>116</b> of the bellows <b>70</b>, shown in <figref idrefs="DRAWINGS">FIGS. 13-15</figref>, has a slope that corresponds to the slope of the shoulder <b>98</b> of the float <b>68</b>, shown in <figref idrefs="DRAWINGS">FIGS. 9-12</figref>.

In this embodiment, the diameter “g” of the opening <b>115</b> of the upper end <b>106</b> of the bellows <b>70</b> defined by the interior wall <b>114</b> is smaller than the diameter “d” of the upper end <b>86</b> of the float <b>68</b>, shown in <figref idrefs="DRAWINGS">FIG. 9</figref>, and smaller than the diameter “e” of the tubular structure <b>90</b> of the float <b>68</b>, also shown in <figref idrefs="DRAWINGS">FIG. 9</figref>. During centrifugation, the diameter “g” of the bellows <b>70</b> increases in size beyond the diameter “d” of the float and enables the venting of air from within the mechanical separator <b>44</b>. This allows the neck <b>96</b> of the float <b>68</b>, shown in <figref idrefs="DRAWINGS">FIG. 9</figref>, to pass through the upper end <b>106</b> of the bellows <b>70</b> but restrains the shoulder <b>98</b> of the float <b>68</b> against the interior restraining surface <b>116</b> of the interior wall <b>114</b> of the bellows <b>70</b>. The tubular structure <b>90</b> of the float is not able to pass through the upper end <b>106</b> of the bellows <b>70</b>.

Portions of the exterior wall of the bellows <b>70</b> between the deformable sealing portion <b>112</b> and the lower end <b>108</b> define a generally cylindrical ballast mounting section <b>118</b> having an outer diameter “h” structured to receive the ballast <b>72</b> of the mechanical separator <b>44</b> thereon.

As shown in <figref idrefs="DRAWINGS">FIGS. 16-19</figref>, the ballast <b>72</b> of the mechanical separator <b>44</b> includes a generally cylindrical section <b>120</b> having an interior surface <b>122</b> structured to engage the ballast mounting section <b>118</b> of the bellows <b>70</b>, shown in <figref idrefs="DRAWINGS">FIGS. 13-15</figref>. In one embodiment, at least a portion of the ballast <b>72</b> extends along the ballast mounting section <b>118</b> of the bellows <b>70</b>, again shown in <figref idrefs="DRAWINGS">FIGS. 13-15</figref>. The ballast <b>72</b> includes opposed upper and lower ends <b>124</b>, <b>126</b>. In one embodiment, the upper end <b>124</b> includes a recess <b>128</b> for receiving the lower end <b>108</b> of the bellows <b>70</b>, shown in <figref idrefs="DRAWINGS">FIGS. 13-15</figref>, therein. The diameter “i” of the recess <b>128</b> is greater than the outer diameter “h” of the bellows <b>70</b>, and the outer diameter “j” of the ballast <b>72</b> is less than the inside diameter “a” of the tube <b>46</b>, as shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. Accordingly, the lower end <b>108</b> of the bellows <b>70</b> may be received within the upper end <b>124</b> of the ballast <b>72</b> and the mechanical separator <b>44</b>, shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, may be received within the interior of the tube <b>46</b>, also shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. In one embodiment, the diameter “i” of the ballast <b>72</b> is equal to the diameter “h” of the bellows <b>70</b>. Optimally, the ballast <b>72</b> may be molded first and the bellows <b>70</b> may be subsequently molded onto the ballast <b>72</b>. In one embodiment, the bellows <b>70</b> and the ballast <b>72</b> exhibit material compatibility such that the bellows <b>70</b> and the ballast <b>72</b> bond together as a result of two-shot molding.

As shown in <figref idrefs="DRAWINGS">FIG. 17</figref>, in one embodiment, the ballast <b>72</b> may include a mechanical interlock recess <b>130</b> extending through the generally cylindrical section <b>120</b>, such as adjacent the upper end <b>124</b>. In another embodiment, the ballast <b>72</b> may include the mechanical interlock recess <b>130</b> within an interior wall <b>131</b>, such as within recess <b>128</b>. A corresponding interlock attachment protrusion <b>132</b> may be provided on the exterior surface of the lower end <b>108</b> of the bellows <b>70</b>, shown in <figref idrefs="DRAWINGS">FIG. 15</figref>, to mechanically engage the bellows <b>70</b> with the ballast <b>72</b>.

In one embodiment, it is desirable that the ballast <b>72</b> of the mechanical separator <b>44</b> be made from a material having a density heavier than the liquid intended to be separated into two phases. For example, if it is desired to separate human blood into serum and plasma, then it is desirable that the ballast <b>72</b> have a density of at least 1.326 gm/cc. In one embodiment, the ballast <b>72</b> can be formed from PET. In yet another embodiment, the bellows <b>70</b>, shown in FIGS. <b>2</b> and <b>13</b>-<b>15</b>, and the ballast <b>72</b>, shown in FIGS. <b>2</b> and <b>16</b>-<b>19</b>, can be co-molded, such as two-shot molded, or co-extruded as a second sub-assembly.

In yet another embodiment, the exterior surface of the ballast <b>72</b> may define an annular recess <b>134</b> circumferentially disposed about a longitudinal axis D of the ballast <b>72</b> and extending into the exterior surface. In this embodiment, the annular recess <b>134</b> is structured to allow for an automated assembly to engage the second sub-assembly, including the bellows and the ballast for joinder with the first sub-assembly, including the pierceable head and the float.

As shown in <figref idrefs="DRAWINGS">FIGS. 20-22</figref>, when assembled, the mechanical separator <b>44</b> includes a pierceable head <b>66</b> engaged with a portion of a float <b>68</b>, and a bellows <b>70</b> circumferentially disposed about the float <b>68</b> and engaged with the shoulder <b>98</b> of the float <b>68</b>, and a ballast <b>72</b> disposed about the float <b>68</b> and engaged with a portion of the bellows <b>70</b>. As shown in <figref idrefs="DRAWINGS">FIGS. 20-22</figref>, the pierceable head <b>66</b> can be at least partially received within the float <b>68</b>. The bellows <b>70</b> can be disposed about the float <b>68</b> and the shoulder <b>98</b> of the float <b>68</b> can be mechanically engaged with the restraining surface <b>116</b> of the bellows <b>70</b>. The ballast <b>72</b> can be circumferentially disposed about the float <b>68</b> and at least a portion of the bellows <b>70</b>, and the mechanical interlock recess <b>130</b> and the attachment protrusion <b>132</b> can mechanically secure the bellows <b>70</b> with the ballast <b>72</b>. Optimally, the bellows <b>70</b> and the ballast <b>72</b> may be two-shot molded and the mechanical interlock may further secure the ballast <b>72</b> and the bellows <b>70</b>.

In one embodiment, the first sub-assembly including the pierceable head <b>66</b> and the float <b>68</b>, and the second sub-assembly including the bellows <b>70</b> and the ballast <b>72</b> can be separately molded or extruded and subsequently assembled. Maintenance of the float density within the specified tolerances is more easily obtained by using a standard material that does not require compounding with, for example, glass micro-spheres in order to reduce the material density. In one embodiment, the material of the float <b>68</b> is polypropylene with a nominal density of about 0.902 gm/cc. In addition, co-molding, such as two-shot molding, the first sub-assembly and the second sub-assembly reduces the number of fabrication steps required to produce the mechanical separator <b>44</b>.

As shown in <figref idrefs="DRAWINGS">FIG. 23</figref>, the assembled mechanical separator <b>44</b> may be urged into the bottom recess <b>62</b> of the closure <b>42</b>. This insertion engages the flanges <b>64</b> of the closure <b>42</b> with the neck <b>96</b> of the float <b>68</b> or against the pierceable head <b>66</b>. During insertion, at least a portion of the pierceable head <b>66</b> will deform to accommodate the contours of the closure <b>42</b>. In one embodiment, the closure <b>42</b> is not substantially deformed during insertion of the mechanical separator <b>44</b> into the bottom recess <b>62</b>. In one embodiment, the mechanical separator <b>44</b> is engaged with the closure <b>42</b> by an interference fit of the pierceable head <b>66</b> and the bottom recess <b>62</b> of the closure <b>42</b>.

Referring again to <figref idrefs="DRAWINGS">FIG. 23</figref>, the pierceable head <b>66</b> and the bellows <b>70</b> are physically isolated from one another by a portion of the float <b>68</b>, such as the neck <b>96</b>. This isolation allows for the pierceable head <b>66</b> to control both the release load from the closure <b>42</b> and the amount of deformation caused by application of a puncture tip through the access portion <b>74</b> independent of the bellows <b>70</b>. Likewise, the bellows <b>70</b> may control the seal load with the tube <b>46</b>, shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, during applied centrifugal rotation independent of the restraints of the pierceable head <b>66</b>.

As shown in <figref idrefs="DRAWINGS">FIGS. 24-25</figref>, the subassembly including the closure <b>42</b> and the mechanical separator <b>44</b> are inserted into the open top end of the tube <b>46</b>, such that the mechanical separator <b>44</b> and the bottom end <b>58</b> of the closure <b>42</b> lie within the tube <b>46</b>. The mechanical separator <b>44</b>, including the bellows <b>70</b>, will sealingly engage the interior of the cylindrical sidewall <b>52</b> and the open top end of the tube <b>46</b>. The assembly including the tube <b>46</b>, the mechanical separator <b>44</b> and the closure <b>42</b> may then be inserted into a needle holder <b>136</b> having a puncture tip <b>138</b>, such as a needle, extending therethrough. Optionally, the closure <b>42</b> may be at least partially surrounded by a shield, such as a Hemogard® Shield commercially available from Becton Dickinson and Company, to shield the user from droplets of blood in the closure <b>42</b> and from potential blood aerosolisation effects when the closure <b>42</b> is removed from the tube <b>46</b>.

As shown in <figref idrefs="DRAWINGS">FIG. 26</figref>, a liquid sample is delivered to the tube <b>46</b> by the puncture tip <b>138</b> that penetrates the septum of the top end <b>56</b> of the closure <b>42</b> and the access portion <b>74</b> of the pierceable head <b>66</b>. For purposes of illustration only, the liquid is blood. Blood will flow through the central passage <b>94</b> of the float <b>68</b> and to the closed bottom end <b>48</b> of the tube <b>46</b>. The puncture tip <b>138</b> will then be withdrawn from the assembly. Upon removal of the puncture tip <b>138</b>, the closure <b>42</b> will reseal itself. The pierceable head <b>66</b> will also reseal itself in a manner that is substantially impervious to fluid flow.

As shown in <figref idrefs="DRAWINGS">FIG. 27</figref>, when the assembly is subjected to an applied rotational force, such as centrifugation, the respective phases of the blood will begin to separate into a denser phase displaced toward the bottom <b>58</b> of the tube <b>46</b>, and a less dense phase displaced toward the top <b>50</b> of the tube <b>46</b>. The applied centrifugal force will urge the ballast <b>72</b> of the mechanical separator <b>44</b> toward the closed bottom end and the float <b>68</b> toward the top end of the tube <b>46</b>. This movement of the ballast <b>72</b> will generate a longitudinal deformation of the bellows <b>70</b>. As a result, the bellows <b>70</b> will become longer and narrower and will be spaced concentrically inward from the inner surface of the cylindrical sidewall <b>52</b>. Accordingly, lighter phase components of the blood will be able to slide past the bellows <b>70</b> and travel upwards, and likewise, heavier phase components of the blood will be able to slide past the bellows <b>70</b> and travel downwards.

Initially, the neck <b>96</b> of the mechanical separator <b>44</b> will be engaged with the flanges <b>64</b> of the closure <b>42</b>. However, upon application of applied centrifugal force, the mechanical separator <b>44</b> is subject to a force that acts to release the mechanical separator <b>44</b> from the closure <b>42</b>. In one embodiment, the closure <b>42</b>, particularly the flanges <b>64</b>, are not dimensionally altered by the application of applied centrifugal force and, as a consequence, do not deform. It is noted herein, that the longitudinal deformation of the bellows <b>70</b> during applied centrifugal force does not affect or deform the pierceable head <b>66</b> as the pierceable head <b>66</b> and the bellows <b>70</b> are isolated from one another by the neck <b>96</b> of the float <b>68</b>.

In one embodiment referring to <figref idrefs="DRAWINGS">FIGS. 27A-27B</figref>, during centrifuge, the negative buoyancy F_Ballastof the ballast <b>72</b> opposes the positive buoyancy F_Floatof the float <b>68</b> creating a differential force which causes the bellows <b>70</b> to contract away from the interior surface of the sidewall <b>52</b> of the tube <b>46</b>. This elongation of the bellows <b>70</b> causes an opening <b>71</b> between the float <b>68</b> and the sealing surface <b>73</b> of the bellows <b>70</b> under load. Once the opening <b>71</b> is formed between the float <b>68</b> and the sealing surface <b>73</b> of the bellows <b>70</b>, as shown in <figref idrefs="DRAWINGS">FIG. 27A</figref>, air trapped within the mechanical separator <b>44</b> may be vented through the opening <b>71</b> into the tube at a location above the mechanical separator <b>44</b>. In this configuration, the bellows <b>70</b> deform away from the float <b>68</b> allowing venting to occur therebetween. After centrifugation, as shown in <figref idrefs="DRAWINGS">FIG. 27B</figref>, the bellows <b>70</b> resiliently returns to the undeformed position and re-sealingly engages the interior surface of the sidewall <b>52</b> of the tube <b>46</b>. Thus, the opening <b>71</b> between the float <b>68</b> and the sealing surface <b>73</b> of the bellows <b>70</b> is sealed as the sealing surface <b>73</b> of the bellows <b>70</b> contacts the float <b>68</b> at contact surface <b>75</b>. With reference to <figref idrefs="DRAWINGS">FIGS. 5-6</figref>, during centrifuge, the slits <b>85</b> positioned within the pierceable head portion <b>66</b> may open due to the elongation of the pierceable head portion material, allowing air trapped within the interior of the float <b>68</b> to be vented therethrough.

As noted above, the mechanical separator <b>44</b> has an overall density between the densities of the separated phases of the blood. Consequently, as shown in <figref idrefs="DRAWINGS">FIG. 28</figref>, the mechanical separator <b>44</b> will stabilize in a position within the tube <b>46</b> such that the heavier phase components <b>140</b> will be located between the mechanical separator <b>44</b> and the closed bottom end <b>48</b> of the tube <b>46</b>, while the lighter phase components <b>142</b> will be located between the mechanical separator <b>44</b> and the top end of the tube <b>50</b>.

After this stabilized state has been reached, the centrifuge will be stopped and the bellows <b>70</b> will resiliently return to its unbiased state and into sealing engagement with the interior of the cylindrical sidewall <b>52</b> of the tube <b>46</b>. The foamed liquid phases may then be accessed separately for analysis.

In an alternative embodiment, as shown in <figref idrefs="DRAWINGS">FIGS. 29-33</figref>, the mechanical separator <b>44</b><i>a </i>may include one or more ballast snaps <b>200</b> for preventing the float <b>68</b><i>a </i>from passing entirely through the bellows <b>70</b><i>a </i>under applied load. The ballast snaps <b>200</b> may be co-molded with the ballast <b>72</b><i>a </i>to limit the movement of the float <b>68</b><i>a </i>with respect to the ballast <b>72</b><i>a</i>, such as by contacting and being restrained by a restraining surface <b>70</b><i>x </i>of the float <b>68</b><i>a </i>under applied load. As shown in detail in <figref idrefs="DRAWINGS">FIG. 33</figref>, the ballast snaps <b>200</b> may include a restraint portion <b>201</b> for engaging a corresponding recess <b>202</b> within the bellows <b>70</b><i>a. </i>

In another alternative embodiment, as shown in <figref idrefs="DRAWINGS">FIG. 34</figref>, the bellows <b>70</b><i>b </i>may have a tapered profile <b>300</b> adjacent the recess <b>202</b> for corresponding engagement with the restraint portion <b>201</b> of the ballast snaps <b>200</b> of the ballast <b>72</b><i>b</i>. The tapered profile <b>300</b> of the bellows <b>70</b><i>b </i>may minimize the formation of bellows pinching due to axial movement of the ballast <b>72</b><i>b. </i>

In another alternative embodiment, a first sub-assembly <b>400</b> including a pierceable head <b>66</b><i>c </i>and a float <b>68</b><i>c </i>may be co-molded as shown in <figref idrefs="DRAWINGS">FIGS. 35-36</figref>. The first sub-assembly <b>400</b> may include a relief ring <b>402</b> for mating adaptation with the ballast (shown in <figref idrefs="DRAWINGS">FIGS. 37-38</figref>) to limit relative travel during assembly and application of accelerated forces. The pierceable head <b>66</b><i>c </i>may be provided with a target area dome <b>403</b> to reduce tenting and to facilitate the shedding of debris therefrom. The pierceable head <b>66</b><i>c </i>may also be provided with a rigid halo surface <b>404</b> to increase launch load and reduce movement of the mechanical separator during insertion into the closure. As shown in <figref idrefs="DRAWINGS">FIGS. 37-38</figref>, the second sub-assembly <b>408</b> including a ballast <b>72</b><i>c </i>and a bellows <b>70</b><i>c</i>, may also be co-molded. As shown in <figref idrefs="DRAWINGS">FIG. 37</figref>, protrusions <b>410</b> on the bellows <b>70</b><i>c </i>may engage with corresponding recesses <b>412</b> within the ballast <b>72</b><i>c </i>to form a locking structure <b>413</b> to improve bond strength and securement of the bellows <b>70</b><i>c </i>and ballast <b>72</b><i>c</i>. In one embodiment, a plurality of protrusions <b>410</b> and corresponding recesses <b>412</b> are provided within the bellows <b>70</b><i>c </i>and ballast <b>72</b><i>c</i>, respectively. As shown in <figref idrefs="DRAWINGS">FIGS. 37-38</figref>, a relief ring <b>414</b> may be circumferentially provided about the ballast <b>72</b><i>c </i>to assist in assembly of the second sub-assembly <b>408</b> with the first sub-assembly <b>400</b>, shown in <figref idrefs="DRAWINGS">FIGS. 35-36</figref>.

The assembled mechanical separator <b>420</b> is shown in <figref idrefs="DRAWINGS">FIGS. 39-40</figref> including the joined first sub-assembly <b>400</b> (shown in <figref idrefs="DRAWINGS">FIGS. 35-36</figref>) and the second sub-assembly <b>408</b> (shown in <figref idrefs="DRAWINGS">FIGS. 37-38</figref>). In one embodiment, the assembled mechanical separator <b>420</b> may be scaled to fit within a 13 mm collection tube (not shown).

In accordance with yet another embodiment of the present invention, as shown in <figref idrefs="DRAWINGS">FIGS. 41-47</figref>, a mechanical separator <b>500</b> may include a ballast <b>572</b>, a bellows <b>570</b>, a float <b>568</b>, and a pierceable head <b>566</b> as similarly described above. In this configuration, the float <b>568</b> and the pierceable head <b>566</b> may be co-formed or separately formed and subsequently assembled into a first sub-assembly, as described above. Referring specifically to <figref idrefs="DRAWINGS">FIG. 48</figref>, the float <b>568</b> may include an upper portion <b>570</b> having a profile P adapted for receiving the pierceable head portion <b>566</b>, shown in <figref idrefs="DRAWINGS">FIGS. 49-50</figref>, in such a fashion that the thickness T of the pierceable head portion <b>566</b> is substantially uniform across the diameter D of the pierceable head portion <b>566</b>, shown in <figref idrefs="DRAWINGS">FIG. 49</figref>. In one configuration, the upper portion <b>570</b> of the float <b>568</b> may have a recess <b>571</b> and the pierceable head portion <b>566</b> may have a corresponding protrusion <b>572</b> for mating with the recess <b>571</b> of float <b>568</b>. In another configuration, the upper portion <b>570</b> of the float <b>568</b> may have a protrusion <b>573</b>, such as a protrusion <b>573</b> flanked by corresponding recesses <b>574</b>. The pierceable head portion <b>566</b> may also have a protrusion <b>575</b> having a mating surface <b>576</b> for abutting a corresponding surface <b>577</b> of the protrusion <b>573</b> of the float <b>568</b>. The protrusion <b>575</b> of the pierceable head portion <b>566</b> may also include flanked protrusions <b>578</b> for engaging the corresponding recesses <b>574</b> of the float <b>568</b>. The pierceable head portion <b>566</b> may be provided over the upper portion <b>570</b> such that the thickness T of the pierceable head portion <b>566</b> is uniform over the opening <b>579</b> of the float <b>568</b>. In another embodiment, the pierceable head portion <b>566</b> may be provided over the upper portion <b>570</b> such that the thickness T of the pierceable head portion <b>566</b> is uniform over both the opening <b>579</b> of the float <b>566</b> and the surrounding ridge <b>581</b> of the float <b>566</b>.

Referring once again to <figref idrefs="DRAWINGS">FIGS. 41-47</figref>, the ballast <b>572</b> and the bellows <b>570</b> may be co-formed or separately formed and subsequently assembled into a second sub-assembly, as described above. In one embodiment, the bellows <b>570</b> may include a protrusion <b>540</b>, and the ballast <b>572</b> may include a corresponding recess <b>541</b> for receiving the protrusion <b>540</b> therein. The protrusion <b>540</b> and the recess <b>541</b> may correspondingly engage to form a locking structure <b>542</b>, such that the ballast <b>572</b> and the bellows <b>570</b> are joined, and to improve bond strength and securement. In another embodiment, the bellows <b>570</b> may include a plurality of protrusions <b>540</b> space about a circumference of the bellows <b>570</b>, and the ballast <b>572</b> may include a plurality of corresponding recesses <b>541</b> spaced about a circumference of the ballast <b>572</b>.

The mechanical separator <b>500</b>, shown in <figref idrefs="DRAWINGS">FIGS. 41-47</figref> is shown in <figref idrefs="DRAWINGS">FIGS. 51-53</figref> disposed within a specimen collection container <b>530</b> and a closure <b>532</b>, as described herein.

As shown in <figref idrefs="DRAWINGS">FIGS. 54-56</figref>, an alternative closure <b>42</b><i>d </i>may be utilized with the mechanical separator <b>420</b> of the present invention. In one embodiment, the closure <b>42</b><i>d </i>includes a receiving well <b>422</b> disposed within a portion of the closure adapted to receive a puncture tip (not shown) therein. The receiving well <b>422</b> may have any suitable dimensions to assist in centering the closure <b>42</b><i>d </i>with the puncture tip. In another embodiment, the receiving well <b>422</b> may include a tapered profile <b>423</b> for angling the puncture tip to the center <b>424</b> of the closure <b>42</b><i>d</i>. In yet another embodiment, as shown in <figref idrefs="DRAWINGS">FIGS. 57-58A</figref>, an alternative closure <b>42</b><i>e </i>may be utilized with the mechanical separator <b>420</b> of the present invention. In this configuration, the closure <b>42</b><i>e </i>may include an enlarged receiving well <b>422</b><i>a </i>adapted to receive a puncture tip (not shown) therein. The closure <b>42</b><i>e </i>may also include a smaller chamfered surface <b>483</b> adjacent the lower end <b>421</b> of the closure <b>42</b><i>e </i>for engaging a portion of the mechanical separator <b>420</b>. In one embodiment, the chamfered surface <b>483</b> may include a first angled surface <b>484</b> and a second angled surface <b>485</b>, with the first angled surface <b>484</b> having a greater angle than the second angled surface <b>485</b> for improving release of the mechanical separator <b>420</b> from the closure <b>42</b><i>e. </i>

In accordance with yet another embodiment of the present invention, shown in <figref idrefs="DRAWINGS">FIG. 59</figref>, a mechanical separator <b>600</b> may include a pierceable head portion <b>666</b>, a float <b>668</b>, a bellows <b>670</b>, and a ballast <b>672</b> as described herein. In one configuration, the float <b>668</b> may be provided with a moveable plug <b>620</b> disposed within an interior portion <b>622</b> of the float <b>668</b>. In one embodiment, the moveable plug <b>620</b> may be formed from the same material as the float <b>668</b>, and in another embodiment, the moveable plug <b>620</b> may be formed from a material having substantially the same density as the density of the float <b>668</b>. In yet another embodiment, the moveable plug <b>620</b> may be inserted within an interior portion <b>622</b> of the float <b>668</b> after formation of the float <b>668</b>.

In certain situations, a mechanical separator <b>600</b> including a float <b>668</b> having a moveable plug <b>620</b> may be advantageous. For example, certain testing procedures require that a sample be deposited into a specimen collection container and that the specimen collection container be subjected to centrifugal force in order to separate the lighter and heavier phases within the sample, as described herein. Once the sample has been separated, the specimen collection container and sample disposed therein may be frozen, such as at temperatures of about −70° C., and subsequently thawed. During the freezing process, the heavier phase of the sample may expand forcing a column of sample to advance upwardly in the specimen collection container and through a portion of the interior portion <b>622</b> of the float <b>668</b> thereby interfering with the barrier disposed between the lighter and heavier phases. In order to minimize this volumetric expansion effect, a moveable plug <b>620</b> may be provided within the interior portion <b>622</b> of the float <b>668</b>.

The moveable plug <b>620</b> may be provided with a transverse hole <b>623</b> which is substantially aligned with a transverse hole <b>624</b> provided in the float <b>668</b> in the initial position, shown in <figref idrefs="DRAWINGS">FIG. 60</figref>, and is substantially blocked by a blocking portion <b>625</b> of the float <b>668</b> in the displaced position, as shown in <figref idrefs="DRAWINGS">FIG. 61</figref>. In one embodiment, the transverse hole <b>624</b> of the moveable plug <b>620</b> is disposed substantially perpendicular to a longitudinal axis R of the moveable plug <b>668</b>. The moveable plug <b>668</b> may also be provided with a longitudinal hole <b>626</b> that is substantially aligned with the interior portion <b>622</b> of the float <b>668</b> to allow sample to be directed therethrough upon introduction of a sample into the mechanical separator, as discussed above.

Referring to <figref idrefs="DRAWINGS">FIG. 60</figref>, in the initial position a sample is introduced into the mechanical separator disposed within a specimen collection container (not shown) through the pierceable head portion <b>666</b>, through the longitudinal hole <b>626</b> of the moveable plug <b>620</b> and through the interior portion <b>622</b> of the float <b>668</b>. After sampling and during application of centrifugal force to the mechanical separator, air trapped within the interior portion <b>622</b> of the float <b>668</b> may be vented through the transverse hole <b>623</b> of the moveable plug and the transverse hole <b>624</b> of the float <b>668</b> and released from the mechanical separator <b>600</b>. Specifically, air may be vented from between the float <b>668</b> and the bellows <b>670</b> as described herein.

Referring to <figref idrefs="DRAWINGS">FIG. 61</figref>, once the sample is separated into lighter and denser phases within the specimen collection container (not shown) the sample may be frozen. During the freezing process, the denser portion of the sample may expand upwardly. In order to prevent the upwardly advanced denser portion of the sample from interfering with the lighter phase, and to prevent the denser portion of the sample from escaping the float <b>668</b>, the moveable plug <b>620</b> advances upwardly with the expansion of the denser phase of the sample. As the moveable plug <b>620</b> is upwardly advanced, the transverse hole <b>623</b> of the moveable plug <b>620</b> aligns with a blocking portion <b>625</b> of the float <b>668</b>, which prevents sample from exiting the moveable plug <b>620</b> and interior portion <b>622</b> of the float <b>668</b> through the transverse hole <b>623</b>. The moveable plug <b>620</b> is adapted to advance with the expanded column of denser material present within the interior portion <b>622</b> of the float during freezing. It is anticipated herein, that the moveable plug <b>620</b> may be restrained at an upper limit of the pierceable head portion <b>666</b>, shown schematically in <figref idrefs="DRAWINGS">FIGS. 59-61</figref>. In this configuration, the elasticity of the pierceable head portion <b>666</b> acts as a stretchable balloon to constrain the moveable plug <b>620</b> within the mechanical separator <b>600</b>.

The advancement of the moveable plug <b>620</b> may be entirely passive and responsive to the externally applied freezing conditions of the sample. In certain instances, the moveable plug <b>620</b> may also be provided to return to its initial position upon subsequent thawing of the sample.

In yet another embodiment, as shown in <figref idrefs="DRAWINGS">FIGS. 62-64</figref>, a mechanical separator <b>700</b> may include a bellows <b>770</b>, a ballast <b>772</b>, as described herein, and a solid float <b>768</b> that does not require a pierceable head portion. In this configuration, it is anticipated that the mechanical separator <b>700</b> may be restrained within a specimen collection container <b>720</b> in an initial position. In one configuration, the mechanical separator <b>700</b> may be restrained with the specimen collection container <b>720</b> due to a frictional interference with a portion of the sidewall <b>722</b> of the specimen collection container <b>720</b>. In another embodiment, the specimen collection container <b>720</b> may include a first portion <b>724</b> having a first diameter E and a second portion <b>726</b> having a second diameter F, with the first diameter E being larger than the second diameter F. In this configuration, the mechanical separator <b>700</b> may be restrained at the interface of the first portion <b>724</b> and the second portion <b>726</b>.

During introduction of a sample into the specimen collection container <b>720</b>, a needle <b>730</b> pierces a portion of the closure <b>740</b> and introduces a sample into the interior <b>745</b> of the specimen collection container <b>720</b>. It is anticipated herein that the needle <b>730</b> does not pierce the float <b>768</b> but rather introduces the sample onto a top surface of the float <b>768</b>. Sample is then directed around the mechanical separator <b>700</b> and passes into the lower portions of the specimen collection container <b>720</b>. After the sample is introduced into the interior <b>745</b> of the specimen collection container <b>720</b>, the needle is removed and the closure re-seals. Upon application of centrifugal force, the mechanical separator <b>700</b> disengages from a restrained position with the sidewall <b>722</b> of the specimen collection container <b>720</b> upon deformation of the bellows <b>770</b> as described herein. In one configuration, at least one of the mechanical separator <b>700</b> and the specimen collection container <b>720</b> may include a recess for allowing sample to pass between the mechanical separator <b>700</b> and the sidewall <b>722</b> of the specimen collection container <b>720</b> during introduction of the sample.

In accordance with yet another embodiment, as shown in <figref idrefs="DRAWINGS">FIG. 65</figref>, a separation component <b>800</b> may be provided between a portion of the bellows <b>770</b> and the sidewall <b>722</b> of the specimen collection container <b>720</b> to assist in at least one of the restraint of the bellows <b>770</b> with the sidewall <b>722</b>, and the passage of sample around the bellows <b>770</b> upon entry of the sample into the specimen collection container. In this configuration, the separation component <b>800</b> may be a sleeve having an angled portion <b>801</b> adapted to allow passage of sample therearound. In accordance with another embodiment, as shown in <figref idrefs="DRAWINGS">FIG. 66</figref>, the specimen collection container <b>720</b> may include a ribbed protrusion <b>802</b>, such as a plurality of radially spaced ribbed protrusions <b>802</b>, spaced inwardly from a portion of the sidewall <b>722</b>. The ribbed protrusion <b>802</b> may allow sample to pass therearound while restraining at least a portion of the bellows <b>770</b> with the sidewall <b>722</b> of the specimen collection container <b>720</b>. In accordance with yet another embodiment, as shown in <figref idrefs="DRAWINGS">FIG. 67</figref>, the specimen collection container <b>720</b> may include a cutout <b>804</b>, such as a plurality of radially spaced cutouts <b>804</b>, within a portion of the sidewall <b>722</b>. The cutouts <b>804</b> may allow sample to pass therethrough while a portion of the sidewall <b>722</b> of the specimen collection container <b>720</b> restrains at least a portion of the bellows <b>770</b>.

In accordance with yet another embodiment, as shown in <figref idrefs="DRAWINGS">FIGS. 68-70</figref>, the mechanical separator <b>700</b> may be restrained against a sidewall <b>722</b> of the specimen collection container <b>720</b> by a washer <b>806</b>. The washer <b>806</b> may constrain a portion of the mechanical separator <b>700</b> such as a portion of the float <b>768</b> through an opening <b>810</b> in the washer <b>806</b>. The washer <b>806</b> may restrain the mechanical separator <b>700</b> with the sidewall <b>722</b> through an interference fit. Optionally, the washer <b>806</b> may be bonded to the sidewall <b>722</b> of the specimen collection container <b>720</b>. The washer <b>806</b> is configured to restrain the mechanical separator <b>700</b> with a portion of the specimen collection container <b>720</b> and to allow sample to pass around the mechanical separator <b>700</b> when introduced into the specimen collection container <b>720</b>. The washer <b>806</b> may hold the mechanical separator <b>700</b> in such a fashion that it substantially prevents the mechanical separator <b>700</b> from occluding the flow of sample into the specimen collection container <b>720</b>. Specifically, the washer <b>806</b> may hold the mechanical separator <b>700</b> in place within the specimen collection container <b>720</b> such that sample may pass between the bellows of the mechanical separator <b>700</b> and the sidewall <b>722</b> of the specimen collection container <b>720</b>. The washer <b>806</b> may also be used with a specimen collection container <b>700</b> having a first portion having a larger diameter and a second portion having a smaller diameter as shown herein. In this configuration, the washer <b>806</b> may prevent the bellows of the mechanical separator <b>700</b> from sealing the junction of the first portion and the second portion of the specimen collection container <b>720</b>, such as where the specimen collection container <b>720</b> “necks down.” In this configuration, the washer <b>806</b> prevents the mechanical separator <b>700</b> from occluding the path of sample into the specimen collection container <b>720</b>.

In one embodiment the washer <b>806</b> includes a plurality of ports <b>820</b> adapted to allow passage of the sample therethrough, as shown in <figref idrefs="DRAWINGS">FIG. 69</figref>. In another embodiment, the washer <b>806</b> includes a cut-away portion <b>822</b> adapted to allow passage of the sample between the washer <b>806</b> and a portion of the sidewall <b>722</b> of the specimen collection container <b>720</b>, as shown in <figref idrefs="DRAWINGS">FIG. 70</figref>.

In accordance with yet another embodiment, as shown in <figref idrefs="DRAWINGS">FIG. 71</figref>, in certain embodiments a portion of the sidewall <b>912</b> of the specimen collection container <b>900</b> may include a protrusion <b>914</b>. Optionally, opposing portions of the sidewall <b>912</b> may include opposing protrusions <b>914</b> adapted to allow a sample entering the specimen collection container <b>900</b> to pass around a portion of the bellows <b>916</b> of a mechanical separator <b>918</b> disposed therein. In this configuration, a portion of the sidewall <b>912</b> having a substantially straight profile may contact a portion of the bellows <b>916</b> to secure the mechanical separator <b>918</b> within the specimen collection container <b>900</b> by an interference fit. Another portion of the sidewall <b>912</b> of the specimen collection container <b>900</b>, such as opposing portions of the sidewall <b>912</b>, may include opposing protrusions having a substantially outwardly curved profile for allowing sample to pass between the sidewall <b>912</b> and the bellows <b>916</b>. In this configuration, the portion of the bellows <b>916</b> aligned with the opposing protrusions <b>914</b> do not touch the sidewall <b>912</b> of the specimen collection container <b>900</b>, establishing a space <b>920</b> for flow of sample therebetween.

Although the present invention has been described in terms of a mechanical separator disposed within the tube adjacent the open end, it is also contemplated herein that the mechanical separator may be located at the bottom of the tube, such as affixed to the bottom of the tube. This configuration can be particularly useful for plasma applications in which the blood sample does not clot, because the mechanical separator is able to travel up through the sample during centrifugation.

While the present invention is described with reference to several distinct embodiments of a mechanical separator assembly and method of use, those skilled in the art may make modifications and alterations without departing from the scope and spirit. Accordingly, the above detailed description is intended to be illustrative rather than restrictive.